Secure communication between various devices is becoming more and more important in an increasingly networked world and represents an essential requirement for the acceptance and therefore also the economic success of the corresponding applications in many areas of application. This includes—depending on the application—various protection goals, for example, ensuring the confidentiality of the data to be transmitted, mutual authentication of the participating nodes, or securing the data integrity.
To achieve these protection goals, suitable cryptographic methods are typically used, which may generally be divided into two different categories: symmetrical methods, in which transmitter and receiver have the same cryptographic key, and asymmetrical methods, in which the transmitter encrypts the data to be transmitted using the public key (i.e., which is also possibly known to a potential attacker) of the receiver, but the decryption may only take place using the associated secret key, which is ideally only known to the receiver. secret keys from channel parameters is discussed in WO 2006/081122 A2. In this process, pilot signal sequences (which may be ones known to both sides) are usually initially sent from the first node to the second node and then pilot signal sequences are sent from the second node to the first node. The respective receiver may estimate channel properties from the received pilot signal sequences and derive suitable parameters for a key generation therefrom. However, if the time deviation between the measurements of the two nodes is too great during this process, different keys may result and the effort for a subsequent key comparison may increase or even make a shared key generation impossible.